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High Power Op Amps

A project log for Playing with Power Ultrasonics

Aimless exploration with power ultrasonic applications

jasmohJasMoH 03/17/2018 at 23:131 Comment

So I've been stalled on selecting the power amplifier for this project for a while. because of the high frequencies (40kHz, possibly higher), class-D amplifiers (i.e. PWM) aren't really viable. Many other projects have just used power MOSFETs that produce square waves and either filter that or just eat the harmonic distortion.

I may yet go with the power FETs due to their expense, but I really wanted to have reasonably sinusoidal outputs. 

Enter the Apex PA341, which purpose built for power ultrasonic devices. Here's the suggested implementation from the datasheet.

This balanced driver pushes 660V at 60 mA continuous! This means I can just take an eBay AD9851 DDS source and just push that out. Sadly that doesn't get me to the 400+ W I was hoping for. 

https://www.digikey.com/product-detail/en/apex-microtechnology/PA341CE/598-1918-ND/2700702

That said, this is a really cool part for higher precision power ultrasonic devices such as motors or similar.

Discussions

DeepSOIC wrote 03/22/2018 at 00:44 point

Hi!

AFAIK, getting a sine wave for these kind of purposes is usually achieved by connecting a square wave generator to an LC circuit, where C is the piezo capacitor. The L-C resonates, the voltage shoots through the roof, and the square wave made by generator becomes a rather small contributor to the voltage across C, i.e. the one will be quite sinusoidal.

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